ARP 155-5401 Main Stud Kit Chrome Moly - 8740 2-Bolt

ARP main stud kits deliver superior clamping force and engine block protection compared to conventional main bolts. This kit features studs manufactured from 8740 chrome moly steel, heat-treated to 200,000 psi tensile strength—significantly stronger than Grade 8 hardware. The precision-engineered design eliminates main cap walk and fretting while protecting threads in your engine block, making it an essential upgrade for serious engine builds.

Key Features:

• 8740 chrome moly steel construction with 200,000 psi tensile strength
• J-form threads rolled after heat-treat for 1000% greater strength than cut threads
• Includes hardened parallel-ground washers and aerospace-quality nuts
• Provides more accurate torque readings by eliminating stud twist during installation
• Reduces stress on engine block threads, extending block life
• Simplifies engine assembly with proper main cap alignment every time
• Exceeds stringent aerospace fastener specifications

ARP recommends main studs over bolts because studs apply clamping force on a single axis without twisting into the block, resulting in more consistent torque values and reduced thread wear. This is particularly critical for aluminum block applications where thread integrity is essential for long-term durability.